This invention relates generally to the art of compensation or isolation of the effect of rotational vibration of an optical system, and more specifically concerns apparatus which introduces a counter disturbance to compensate, in one degree of freedom, for the effect of rotational vibration on a light beam of the optical system which produces the light beam.
Certain optical systems which include a beam generating device, such as, for instance, a laser, have been used to illuminate or target objects located a significant distance, i.e. in the far field, from the optical system. Other optical systems which do not include a beam generating device, such as telescopes, are, on the other hand, used to locate or observe given objects.
When the optical system is mounted on a steady base, such as the earth, the generated beam or the light from the object in the far field will remain steady, for accurate targeting or viewing. However, the optical system in many applications will be mounted on a vehicle or in an aircraft, which are subject to vibration. When the support base of the optical system, e.g. the frame of an aircraft, vibrates, the optical system, typically supported by one or more sets of gimbal axes, will also vibrate, which, in a beam targeting apparatus, for instance, causes the generated beam to vibrate in the far field. This results in the designated object tending to blur, an undesirable effect.
Generally, the attempts to correct such beam vibration have been directed towards stabilizing the platform carrying the optical system upon the gimbal axes. This is, however, in practice difficult to accomplish. Such correction systems are complex and expensive, and do not provide uniformly successful results.
Accordingly, an object of the present invention is to provide a compensation/isolation system which results in the output beam being unaffected by rotational vibration, about one axis, of the optical system producing the beam.
It is a further object of the present invention to provide such a system which is designed to operate when the optical system is vibrating with a support base, and which does not depend on totally isolating the optical system from the vibrating support base.
It is an additional object of the present invention to provide such a system which operates in such a manner that there is little, if any, lag between the vibration of the optics and the corrective action of the system.
It is a further object of the present invention to provide such a system which may be used with similar or equivalent systems for compensation of rotational vibration in all three coordinate axes of a representative system.